Extension ladder



R. C. DOSS EXTENSION LADDER Feb. 6, 1962 2 Sheets-Sheet l Filed Aug. l, 1960 INVENTOR. RO G ER C. D O SS la .wiel

Feb. 6, 1962 R. c. Doss 3,019,851

EXTENSION LADDER Filed Aug. l, 1960 2 Sheets-Sheet 2 FIG. 50(2 I4 IN VEN T 0R.

RGGER C. DOSS es BY jygf,

ited States Patent Oiitice 3,@ l 9,851 Patented Feb. 6, 1 962 3,019,851 EXTENSIN LADDER Roger C. Doss, 2313 Ogden, Omaha, Nebr. Filed Aug. 1, 1960, Ser. No. 46,837 3 Claims. (Cl. 182-1l1) This invention relates to sectional ladders of the type having pivotally mounted rungs extended from opposite sides of a center rail or support member, and in particular pairs of support members, channel-shaped in cross section, positioned back to back providing a center rail with vrungs pivotally mounted in and positioned to fold into the rails, with rails of one section designed to be retained in ends of rails of another section, and with supporting elements at upper and lower ends of the ladder retained on ends of the sections by spring latches.

The purpose of this invention is to provide a sectional ladder in which rungs of the sections fold into the sections and in which supporting elements at upper and lower ends of the ladder are retained in position by spring latches; whereby the complete ladder may be folded into a relatively small package.

Ladders having rungs or steps extended from opposite sides of a center rail have been provided in different designs. However, it has been found difficult to mount the rungs so that they will fold `into the center rail, and it is also diicult to connect supporting elements to ends of the center rail so that the eiements of the ladder may be nested for storage and shipping.`

With this thought in mind this invention contemplates a sectional ladder in which sections thereof and also supporting elements at the ends of the ladder are connected by spring latches, and in which rungs of the ladder are pivotally mounted in openings in the sides of the sections whereby the rungs may be folded into said sections.

The object of this invention is, therefore, to provide a sectional ladder in which the parts nest into a comparatively small package.

Another object of the invention is to provide a sectional ladder in which the parts are secured in assembled relation by spring latches.

Another important object of the invention is to provide a collapsible ladder in which rungs thereof fold into a center rail of the ladder.

It is yet another object of the invention to provide a folding sectional ladder in which supporting elements at upper and lower ends of sections of the ladder are pivotally mounted to compensate for inclined or uneven supporting surfaces.

A further object of the invention is to provide supporting means at the lower end of a sectional ladder in which ground gripping elements are provided to compensate for different angles of inclination of the ladder.

A still further object is to provide a collapsible sectional ladder in which the ladder is of simple and economical construction.

With these and other objects and advantages in View the invention embodies a central rail including pairs of channels positioned back to back with rungs pivotally mounted in side walls of the channels and positioned to fold into the channels, with a head having a U-shaped bracket pivotally mounted therein secured on the upper end of the uppermost section, 'and with a cradle having arcuate ground engaging elements on the ends pivotally mounted on the lower end of the lowerrnost section, the sections, head, and cradle being secured together' by spring latches.

Other features and advantages of the invention will appear from the following description taken in connecv tion with .the drawings, wherein:

FIGURE 1 is a perspective view illustrating the improved sectional ladder.

FIGURE 2 is an end view of the cradle at the lower end of the ladder with part broken away showing the connection of the cradle to the lowermost section of the ladder in section, and also showing one of the ground gripping treads in section.

FIGURE 3 is a vertical section taken at a right angle to the section shown in FIGURE 2, also showing the connection of the cradle to the lower end of the ladder, and showing the ladder in an inclined position in broken lines, the upper portion of the ladder and end portions of the cradle being broken away.

FIGURE 4 is a View showing the mounting of spring latches in ends of the sections of the ladder, parts being broken away.

FIGURE 5 is a view showing open sockets in the ends of the sections for receiving the spring latches shown in FIGURE 4.

FIGURE 6 is a sectional plan through a section of the ladder taken on line 6-6 of FIGURE 7 showing a rung on one side in an extended position, and the rung on the opposite side folded into the section.

FIGURE 7 is a vertical section through a portion of the ladder showing a rung on one side of the ladder extended in full lines, and in the` nested position in broken lines.

While one embodiment of the invention is illustrated in the above-referred-to drawings, it is to be understood that they are merely for the purpose of illustration and that various changes in construction may be resorted to in the course of manufacture'in order that the invention may be utilized to the best advantage according to circumstances which may arise, Without in any manner departingr from the spirit and intention of the device, which is to be limited only in accordance with the appended claims. And while there is stated the primary field of utility of the invention it remains obvious that it may be employed in any other capacity wherein it may be found applicable.

In the accompanying drawings, and in the following specification, the same reference characters are used to ldesignate the same parts and elements throughout, and in which the numeral it) refers to the invention in its entirety, numeral 12 indicating a center rail or beam including channel bars 14 and 16, numeral 18 indicating rungs pivotally mounted by bolts 20 in the channel bars, numeral 22 a U-shaped bracket pivotally mounted on a head 24 on the upper end of the uppermost section 26 of the center rail, and numeral 28 a rod of a cradle 30 pivotally mounted by a bolt 32 on the lower end of the lowermost section 34 of the rail.

The channel bars 14 and 16 are formed with webs 36 from the edges of which side walls 38 and 40 extend and extended edges of the side walls are provided with flanges 42 and 44. The side walls on one of the sides of the channel bars are provided with sockets 46 and 48, and the sockets arepositioned to receive spring latches 5t) and 52 secured by rivets in the openings 54 of side walls 56 and 58 of splice bars 6d and 62 which arel secured by rivets 64 in the ends of the channel bars of a section of the center beam.

In use the channel bars 14 and 16 are slid over the splice bars 60 yand 62 and over the spring latches S0 and 52 wh-ich project through openings 66 in the side walls 56 and 5S. The spring ylatches 50 and 52 are compressed until the sockets 46 Iand 4S register with the openings 66, and at this time the latches snap into the sockets rigidly retaining the sections of the center beam in assembled relation.

The rungs 18 are provided with hubs 68 through which the bolts 20 extend and the hubs are provided with lugs providing stops 7@ that `are positioned to engage inner surfaces of the webs 36, which are secured together by rivets 72. The extended ends of the rungs are provided with projections 74, to prevent the feet of a person using the ladder slipping from the rungs.

The hubs 68 are provided with bearing sleeves 76 and the ends of the hubs are retained in spaced relation to the side walls 3S and 40 Iby spring cup washers 7S and 80. The bolts 26V are Vprovided with heads 82 on one of the ends and threaded studs 84 having lock nuts S6 thereon extendafrom shoulders 88 at the opposite ends. 'The shoulders prevent the side walls being drawn inwardly to such an extent that the rungs are not free to move from one position to another.

The head 24 is provided with extensions similar to the splice bars 56 and 58 and the extensions are provided with spring latches 89 that snap into sockets 9i) of the bars 14 and 16. The extensions are secured in the head 24, which is rectangular-shaped byrivets 92. The head 24 is provided with a swivel stud 94 having an opening 96 therethrough and the bar of the bracket 22 extendsV through the opening, as shown in FfGURE l. Ends 98 and 100 of the bracket are covered with friction cups 102.

The lower end of the lower section 34 of the center beam extends into a cup 194 in which the lower end of the section is secured by spring latches 166 which :snap into sockets S in the ywall of the cup. The lower end of the cup 104 is provided with depending ltangs 110 and 112 between which :a tongue 114 extended from a hub 116, is secured by the bolt 32. The bolt is provided with a head 118 and a stud 120 havinga threaded end 122 extends from la shoulder 124 on the opposite end. The shoulder 124 prevents binding of the tongue between the tangs, as a lock nut 126 on the stud is tightened.

The hub 116 from which the tongue 114 extends is vsecured on the rod 28 by set screws 12S, `and the ends of the rod are retained in sockets 130 and 132 of substantially semi-circular rockers 134 and 136 by set screws 13S. The sockets 130 and 132 are positioned on hon' zontal bars 14) and 142 which connect upper ends of.

the rockers. The lower surfaces of the rockers are covered with shoes 144 `and 146 that yare provided with .rough outer surfaces land the shoes are secured to the rockers by rivets 148'. The ends ofthe rockers are provided with ground gripping elements 150 that are secured to ends of the rockers by welding or the like. The elements 150 are provided with outwardly extended sections 152 and the lower edges of the sections 152` are formed with teeth 154.

Operation The ladder illustrated in FIGURE l is shown as being formed by two sections. However, it will be understood that the center beam or rail may be formed with as many sections -as may be desired, depending upon the length of the ladder desired.

The sections of the ladder are taken apart Aby pressing the spring latches inwardly and drawing one section or part from another. The head 24 is removed from the upper end by pressing the spring latches 89 inwardly, andthe cup 104 is removed yfrom the lower end by pressing the latches 106 inwardly. By this means the parts may be nested in a relatively small package.

In assembling the ladder it is only necessary to insert the end of one section into the end of another section and force the sections together until the spring latches snap into the sockets. The head 24 and cup 104 are placed on the ends of the uppermost and lowermost sections by similar means.

The rungs 18, which fold into the channel-shaped sections or rails may be of any suitable size, and the rungs may be spaced any suitable distance on the rails or center beam.

From the foregoing specification it will become apparent that the invention disclosed will adequately accomplish the functions for which it has been designed and in an economical manner, and that its simplicity, accuracy, and ease of operation are such as to provide a relatively inexpensive ladder considering what it will accomplish, and that it will iind an important place in the art to which it appertains when once placed on the market.

it is thought that persons skilled in the art to which the invention relates will be able to obtain a clear under'-A standing of the invention after considering the description in connection with the drawings. -Therefore, a more lengthy description is regarded as unnecessary. I

`Changes in shape, size, and arrangement of details and parts such as come within the purview of the invention claimed may be resorted to in actual practice if desired.

Having now described the invention that which is claimed to be new and desired to be procured by Letters Patent, is:

l. ln a sectional ladder, the combination which comprises a center` beam including a .plurality of sections channel-shaped in cross section and positioned back to back, each having continuous longitudinally disposed openings in the sides, sockets spaced inwardly from one of the ends thereof, and splice bars with spring latches therein extended from ends opposite to the ends in which the sockets are positioned, the spring latches of one seca tion being positioned to snap into the sockets of Ian adv' joining section in 'assembling the beam, rungs4 having hubs with lugs extended from lower surfaces and having projections on outer ends pivotally mounted in .the sec tions and positioned to, selectively, fold into the sections or extend outwardly from the sections, said lugs being below the pivotal mountings of the rungs and positioned to support the rungsV in horizontal positions, and adjus table supporting means on the lower end of the beam;

2. In la sectional ladder, the combination which corn prises a center beam including a plurality of sections, each having a pair of bars channel-shaped in cross section positioned back to back providing continuous openings in outer sides, each of said bars having sockets spaced inwardly from one of the ends thereof and splice bars with spring latches therein extended from opposite ends, the spring latches of the bars of one section being posi; tioned to snap into the sockets of lan adjoining section, rungs extended from hubs positioned in the sections, bolts mounted in sides of the bars and extended through the hubs pivotally mounting the rungs in the sections fwhereby the rungs, selectively, extend from the sections or fold into the sections, the hubs having lugs below the axes of the pivotal mountings thereof positioned to engage the backs of the bars for retaining the rungs in outwardly extended horizontally disposed positions, and a cradle having arcuate ground engaging elements on ends thereof pivotally mounted on the lower end of the lowermost section of the ladder.

3, In a sectional ladder, the combination which comprises a center beam including a plurality of sections, each comprising a pair of rails, channel-shaped in cross section and each having sockets spaced inwardly from one of the ends and splice bars with spring latches therein extended from opposite ends, rungs pivotally mounted in the rails, said rungs having hubs on inner ends and said hubs having lugs extended from lowerl surfaces yand positioned to engage inner surfaces of backs of the rails, the hubs being positioned on bolts extended through sides of the rails, a head having spl-ice bars with spring latches therein designed to rbe positioned on an end of one section, a cup having sockets therein designed to receive an end of a section with splice bars of the section positioned in the,V cup and with spring latches of the splice bars 4in the sockets of the cup, said cup having tangs depending from the lower end, a rod pivotally 5 mounted in -sad tangs, `and semi-circular ground engaging elements with rough outer surfaces and with brackets having teeth thereon extended from the ends carried lby ends of the rod.

References Cited in the file of this patent UNITED STATES PATENTS 272,163 Shaver et a1. Feb. 13, 1883 

